The present invention relates generally to a calibration device and calibration method. In particular, the present invention relates to devices and methods for calibrating an optical wavefront system that measures optical aberrations in a patient's eye.
Laser eye surgical systems typically employ a system that can track and measure the optical characteristics of the patient's eye. One promising eye measurement system uses wavefront technology that allows the surgeon to measure and treat low order and high order aberrations in and on the patient's eye. A wavefront measurement of the eye creates a high order aberration map that permits assessment of aberrations throughout the optical pathway of the eye, e.g., both internal aberrations and aberrations on the corneal surface. The aberration information can then be used to compute a custom ablation pattern so that the surgical laser system can correct the aberrations of the patient's eye.
One exemplary wavefront technology system is the VISX WaveScan™ System, which uses Hartmann-Shack wavefront sensors that can quantify aberrations throughout the entire optical system, including first and second-order sphero-cylindrical errors, coma, and third through sixth order aberrations related to coma, astigmatism, and spherical aberrations. The aberrations can be displayed to the surgeon in the form of an AcuityMap™ and/or an aberration map, for example.
However, in order to accurately map the aberrations in the patient's eye, it is required that the wavefront system be properly calibrated. If the eye measurement systems are not properly calibrated, the information derived from the wavefront will not provide the correct aberration pattern and an incorrect ablation pattern may thereafter be chosen.
Consequently, what are needed are devices and methods which can calibrate eye measurement systems, such as a wavefront system.